GENERAL INFORMATION 107 



few years by the United States Department of 

 Agriculture and the United States National Her- 

 barium which can be purchased for a small amount 

 from the Superintendent of Documents or, the few 

 out of print, from dealers in second-hand books. 



Hitchcock, A. S. North American Species of Leptochloa. U. S. 



Dept. Agr., Bur. PL Ind. Bull. 33, 24 pp., with plates. 



1903. 

 North American Species of Agrostis. U. S. Dept. Agr., 



Bur. PL Ind. Bull. 68, 68 pp., with plates. 1905. 

 Mexican Grasses in the United States National Herbarium. 



Contr. U. S. Nat. Herb. 17, pp. 181-389. 1913. 

 The North American Species of Ichnanthus; The North 



American Species of Lasiacis. Contr. U. S. Nat. Herb. 



22, 31 pp., with plates. 1920. 

 Revisions of North American Grasses: Isachne, Oplis- 



menus, Echinochloa, and Chaetochloa. Contr. U. S. 



Nat. Herb. 22, pp. 115-208, with text figures. 1920. 

 and Chase, Agnes. The North American Species of 



Panicum. Contr. U. S. Nat. Herb. 15, 396 pp., with 



text figures. 1910. 

 Tropical North American Species of Panicum. Contr. 



U. S. Nat. Herb. 17, pp. 459-539, with text figures. 



1915. 

 Grasses of the West Indies. Contr. U. S. Nat. Herb. 18, 



pp. 261-471. 1917. 

 Griffiths, David. The Grama Grasses: Bouteloua and Related 



Genera. Contr. U. S. Nat. Herb. 14, pp. 343-428, with 



plates. 1912. 

 Merrill, Elmer D. North American Species of Spartina. U. S. 



Dept. Agr., Bur. PL Ind. Bull. 9, 16 pp. 1902. 

 Piper, C. V. North American Species of Festuca. Contr. U. S. 



Nat. Herb. 10, 48 pp., with plates. 1906. 



